[Samba] Panic in 4.23.2 (openat_pathref_fsp_nosymlink -> is_in_path -> mask_match )

[Peter Eriksson]

Found a couple (3 as of right now, from different users on different servers) of core dumps from smbd processes where there seems to be a double-free (or something) causing a panic in mask_match() - connected to “veto files” (we use “veto files = /.zfs/“ in smb.conf). 

https://bugzilla.samba.org/show_bug.cgi?id=15941

Looking at the code in question there seems to have been a number of changes in 4.23 vs 4.22…

It doesn’t happen all the time (I’ve only found three core dumps so far) but it happens fairly regularly. Haven’t found a way to force it to happen yet.

- Peter